JP2001291963A - Multilayered printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered printed wiring board improved in flame resistance, improved in adhesibility with a conductor circuit, and having a solder resist layer formed with an opening into a desired form. SOLUTION: Concerning the multilayer printed wiring board with which conductor circuits and resin insulating layers are formed successively on a substrate, the solder resist layer is formed on the outermost layer, and the solder resist layer contains P atom containing epoxy resins.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board.

[0002]

2. Description of the Related Art Conventionally, build-up multilayer printed wiring boards have been manufactured by a method disclosed in, for example, Japanese Patent Application Laid-Open No. 4-55555. That is, first, a through hole is formed in the copper-clad laminate to which the copper foil is attached, and then a through hole is formed by performing an electroless copper plating process. Subsequently, the surface of the substrate is etched into a conductor pattern to form a conductor circuit, and a roughened surface is formed on the surface of the conductor circuit. Then, after forming a layer of the resin composition on the conductor circuit having the roughened surface, an opening for a via hole is formed, and thereafter, an interlayer resin insulating layer is formed through UV curing and main curing.

Further, after performing a roughening treatment on the interlayer resin insulating layer, a thin film conductor layer is formed, a plating resist is formed on the thin film conductor layer, and a thickening is performed by electroplating. The thin film conductor layer existing under the plating resist is removed by an etchant to form an independent conductor circuit. This step is repeated to sequentially laminate the conductor circuit and the interlayer resin insulation layer, and then apply a solder resist composition to form a solder resist composition layer for protecting the conductor circuit on the outermost layer, An opening is formed for connection to a chip or the like, plating or the like is performed on the exposed conductor circuit, and a solder paste is printed to form a solder bump, thereby completing the manufacture of the build-up multilayer printed wiring board.

In the production of such a multilayer printed wiring board, as a solder resist composition, for example, a (meth) acrylate of a novolak type epoxy resin, an imidazole curing agent, a bifunctional (meth) acrylate monomer, and a molecular weight of 500 A paste-like fluid containing a polymer of (meth) acrylic acid ester of up to about 5,000, a thermosetting resin composed of a bisphenol-type epoxy resin, a photosensitive monomer such as a polyvalent acrylic monomer, a glycol ether-based solvent, etc. A solder resist layer was formed by applying and hardening this.

[0005]

The multilayer printed wiring board having such a solder resist layer is used by mounting an electronic component such as an IC chip. Therefore, when an IC chip or the like is ignited for various reasons, it is desired to be able to withstand it. Specifically, those that pass the UL94 criterion in the UL test standard are desired, and in particular, those that pass the combustion time criterion of 94V-0 are desired.

In addition, the multilayer printed wiring board satisfies the above-mentioned flame retardancy standard, and when forming an opening for a via hole or an opening for a solder pad, a resin insulating layer or a solder of an existing multilayer printed wiring board is required. It is desired that the opening property does not decrease as compared with the resist layer, and it is also desired that the adhesion between the resin insulating layer and the like and the conductor circuit does not decrease. Furthermore, it is also desired that the performance does not decrease when a reliability test is performed.

However, multilayer printed wiring boards having a solder resist layer formed using a conventional solder resist composition have not been satisfactory in terms of flame retardancy.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a solder having excellent flame retardancy, high adhesion to a conductor circuit, and having an opening of a desired shape. An object of the present invention is to provide a multilayer printed wiring board having a resist layer.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies for realizing the above object, and as a result, a multilayer printed wiring board having a solder resist layer containing a P-atom-containing epoxy resin has a difficulty in forming a surface layer portion. It excels in flammability, has high adhesion between the solder resist layer and the conductor circuit, and solves the above-mentioned problem because the solder resist layer has openings of a desired shape formed by exposure, development, and the like. The inventors have found that the invention can be achieved, and have arrived at the invention having the following content as a gist configuration.

That is, the multilayer printed wiring board of the present invention is a multilayer printed wiring board in which a conductive circuit and a resin insulating layer are sequentially formed on a substrate, and a solder resist layer is formed on an outermost layer. The layer is characterized by containing a P atom containing epoxy resin.

In the multilayer printed wiring board of the present invention, the P-atom-containing epoxy resin is preferably an epoxy resin having a divalent phosphoric acid residue and having epoxy groups at both ends.

The epoxy resin having a divalent phosphoric acid residue and having epoxy groups at both ends is represented by the following general formula (1)

[0013]

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(Wherein X ¹ and X ² each represent O or a single bond).

In the multilayer printed wiring board of the present invention, the P-atom-containing epoxy resin is an epoxy resin having a monovalent phosphoric acid residue at one end and an epoxy group at the other end. Is desirable.

The epoxy resin having a monovalent phosphate residue at one end and an epoxy group at the other end is represented by the following general formula (2)

[0017]

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(Wherein, X ³ represents O or a single bond, and R represents an alkyl group having 2 to 8 carbon atoms).

The solder resist layer preferably contains at least one selected from the group consisting of a silicon compound, an aluminum compound and a magnesium compound.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The multilayer printed wiring board of the present invention
A multilayer printed wiring board in which a conductive circuit and a resin insulating layer are sequentially formed on a substrate, and a solder resist layer is formed on an outermost layer, wherein the solder resist layer contains a P atom-containing epoxy resin. I do.

According to the multilayer printed wiring board, since the solder resist layer contains the P-atom-containing epoxy resin, it is excellent in flame retardancy due to the presence thereof. this is,
Since the epoxy resin as the raw material of the solder resist layer contains P atoms, even if the resin starts burning at the time of ignition,
This is because combustion stops once at the atomic portion.

Further, since the solder resist layer formed on the multilayer printed wiring board of the present invention uses an epoxy resin having excellent adhesiveness as a raw material, the adhesiveness between the solder resist layer and the conductor circuit is high. In addition, as a material for the solder resist layer, a material other than the P-atom-containing epoxy resin is the same as that usually used. Is formed.

In the multilayer printed wiring board of the present invention, the solder resist layer contains a P atom-containing epoxy resin. The P-atom-containing epoxy resin is not particularly limited as long as it is a phosphorus-containing epoxy resin. Among them, an epoxy resin having a phosphoric acid residue is desirable, and an epoxy resin having a phosphate ester bond is more desirable. . Specifically, it has a divalent phosphate residue, and
An epoxy resin having an epoxy group at both ends and an epoxy resin having a monovalent phosphoric acid residue at one end and an epoxy group at the other end are desirable.

Examples of the epoxy resin having a divalent phosphoric acid residue and having epoxy groups at both terminals include, for example, a P atom-containing epoxy resin represented by the following general formula (1). .

[0025]

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[0026] (wherein, X ^1, X ^2, respectively, O, or represents. A single bond) wherein when X ¹ and / or X ² is O (oxygen),
The P-atom-containing epoxy resin represented by the general formula (1) has a phosphate ester bond.

In the epoxy resin represented by the general formula (1), a phosphoric acid residue is represented by the following chemical formula (3)

[0028]

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The compound represented by the following chemical formula (4) is bonded to the above-mentioned phosphate residue.

[0030]

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The compound may be represented by the following formula:
The compounds binding to the above phosphate residues may be different from each other.

The epoxy resin having a monovalent phosphoric acid residue at one terminal and an epoxy group at the other terminal includes, for example, a P atom-containing epoxy resin represented by the following general formula (2). Resins.

[0033]

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(In the formula, X ³ represents O or a single bond, and R represents an alkyl group having 2 to 8 carbon atoms.) Here, when X ³ is O (oxygen), The P atom-containing epoxy resin represented by the formula (2) has a phosphate ester bond.

In the epoxy resin represented by the general formula (2), the compound binding to the phosphoric acid residue may be, for example, a compound having an epoxy group at a terminal represented by the chemical formula (4). Good. Examples of the alkyl group include an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, and a tert-butyl group. Of these, a butyl group is preferred.

The content of the P atom-containing epoxy resin in the solder resist layer is desirably 0.1 to 70% by weight. If it is less than 0.1% by weight, the multilayer printed wiring board may not have sufficient flame retardancy, whereas if it exceeds 70% by weight, the flame retardancy of the multilayer printed wiring board is not so much improved.

The solder resist layer desirably contains a silicon compound, an aluminum compound, a magnesium compound or the like as an inorganic filler. These compounds may be contained alone or in combination of two or more.

The silicon compound is not particularly restricted but includes, for example, silica and zeolite. The aluminum compound is not particularly limited, for example,
Alumina, aluminum hydroxide and the like can be mentioned.

The magnesium compound is not particularly restricted but includes, for example, magnesia, dolomite, basic magnesium carbonate and the like. When these compounds are contained in the solder resist layer, the stress generated in the solder resist layer is easily relieved, and as a result, cracks occur in the solder resist layer and peeling occurs with the conductor circuit. Is less likely to occur.

The particle size of the above-mentioned inorganic filler is 0.1-5.
0 μm is desirable. When the particle size is less than 0.1 μm, the effect of relaxing the stress generated in the solder resist layer is not so much obtained. On the other hand, when the particle size exceeds 5.0 μm, the curability of the layer of the solder resist composition is adversely affected. In addition, it may adversely affect the opening property when providing an opening for a solder pad or the like in the layer of the solder resist composition.

The shape of the inorganic filler is not particularly limited, and examples thereof include a spherical shape, an elliptical spherical shape, a crushed shape, and a polyhedral shape. Among them, a spherical shape is preferable because the stress generated in the solder resist layer is easily reduced and it is difficult to form a protrusion on the surface of the solder resist layer.

The content of the inorganic filler in the solder resist layer is desirably 0.1 to 15% by weight. If the content is less than 0.1% by weight, the effect of relaxing the stress generated in the solder resist layer is poor, and if it exceeds 15% by weight, the curability of the layer of the solder resist composition may be adversely affected, In addition, the opening of the solder resist composition layer may be adversely affected when an opening for a solder pad or the like is provided.

The solder resist layer constituting the multilayer printed wiring board of the present invention may be made of, for example, a thermosetting resin, a thermoplastic resin, a thermosetting resin and a thermoplastic resin in addition to the P-atom-containing epoxy resin and the inorganic filler. May be included. Specifically, for example, it is composed of a (meth) acrylate of a novolak epoxy resin, a difunctional (meth) acrylate monomer, a polymer of a (meth) acrylate having a molecular weight of about 500 to 5,000, a bisphenol-type epoxy resin, or the like. Examples thereof include those obtained by polymerizing and curing a solder resist composition composed of a thermosetting resin, a photosensitive monomer such as a polyvalent acrylic monomer, or the like.

The difunctional (meth) acrylic acid ester monomer is not particularly restricted but includes, for example, esters of acrylic acid or methacrylic acid of various diols, and commercially available products manufactured by Nippon Kayaku Co., Ltd. R-604,
PM2, PM21 and the like.

Examples of the (meth) acrylate of the novolak epoxy resin include an epoxy resin obtained by reacting glycidyl ether of phenol novolak or cresol novolac with acrylic acid, methacrylic acid, or the like.

As a method of forming such a layer of the solder resist composition, an uncured solder resist composition containing the above-described P atom-containing epoxy resin or the like is prepared and applied by a roll coater method or the like. After preparing a resin film composed of an uncured solder resist composition,
A method of thermocompression bonding this resin film or the like can be given.

When the above-mentioned inorganic filler is contained in the solder resist layer, it is desirable to add the above-mentioned inorganic filler after dispersing it in a solvent such as methyl ethyl ketone when preparing the above-mentioned solder resist composition. This is because the inorganic filler can be uniformly dispersed in the solder resist layer without aggregating.

The above solder resist composition contains, in addition to phosphorus, a phosphorus compound and an inorganic filler, a (meth) acrylate of the novolak epoxy resin, an imidazole curing agent,
A bifunctional (meth) acrylate monomer, a polymer of a (meth) acrylate ester having a molecular weight of about 500 to 5,000, a thermosetting resin such as a bisphenol-type epoxy resin, a photosensitive monomer such as a polyvalent acrylic monomer, A paste-like fluid containing a glycol ether solvent or the like is desirable. The viscosity is 25 ° C
Is preferably adjusted to 1 to 10 Pa · s.

The imidazole curing agent is not particularly limited, but it is preferable to use an imidazole curing agent which is liquid at 25 ° C. This is because uniform kneading is difficult with powder, and liquid can be kneaded more uniformly. Examples of such a liquid imidazole curing agent include, for example, 1
-Benzyl-2-methylimidazole (manufactured by Shikoku Chemicals,
1B2MZ), 1-cyanoethyl-2-ethyl-4-methylimidazole (2E4MZ-C, manufactured by Shikoku Chemicals)
N), 4-methyl-2-ethylimidazole (2E4MZ, manufactured by Shikoku Chemicals) and the like.

Examples of the glycol ether solvents include:
For example, those having the chemical structure represented by the following general formula (3) are desirable, and more specifically, it is more desirable to use at least one selected from diethylene glycol dimethyl ether (DMDG) and triethylene glycol dimethyl ether (DMTG). These solvents are 3
This is because benzophenone, Michler's ketone, and ethylaminobenzophenone, which are polymerization initiators, can be completely dissolved by heating at about 0 to 50 ° C.

CH ₃ O— (CH ₂ CH ₂ O) _n —CH ₃ (3) (wherein, n represents an integer of 1 to 5)

The solder resist layer having such a configuration has excellent flame retardancy because it contains the P-atom-containing epoxy resin, and the multilayer printed wiring board on which the solder resist layer is formed has a UL test standard. It satisfies the UL94 (flame retardancy test of polymer materials) criteria, among which it satisfies the criteria of 94V-0.

Next, a method of manufacturing the multilayer printed wiring board will be described in the order of steps. (1) In the method for manufacturing a printed wiring board of the present invention, first, a substrate having a conductive circuit formed on a surface of an insulating substrate is prepared.

As the insulating substrate, a resin substrate is desirable. Specifically, for example, a glass epoxy substrate, a polyester substrate, a polyimide substrate, a bismaleimide-triazine resin substrate, a thermosetting polyphenylene ether substrate, a fluororesin substrate, Ceramic substrate, copper clad laminate, R
CC substrate and the like. At this time, a through hole may be provided in the insulating substrate. In this case, the through hole has a diameter of 10
It is desirable to form it using a 0 to 300 μm drill, laser light, or the like.

(2) Next, after performing electroless plating, a conductive circuit-shaped etching resist is formed on the substrate, and the conductive circuit is formed by performing etching. Copper plating is desirable as the electroless plating. In addition, when a through hole for a through hole is provided in an insulating substrate, a through hole is formed by simultaneously performing electroless plating on the wall surface of the through hole for the through hole, thereby forming a through hole between conductor circuits on both surfaces of the substrate. May be electrically connected.

Further, after the electroless plating, a roughening process is usually performed on the surface of the electroless plating layer and the inner wall of the through hole when the through hole is formed. Examples of the roughening forming treatment method include blackening (oxidation) -reduction treatment, spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, Cu treatment
-Ni-P needle-like alloy plating.

As a specific method of the above-mentioned blackening (oxidation) -reduction treatment, NaOH (10 g / l), NaClO ₂
(40 g / l), a blackening treatment using an aqueous solution containing Na ₃ PO ₄ (6 g / l) as a blackening bath (oxidizing bath), and NaO
A method of performing a reduction treatment using an aqueous solution containing H (10 g / l) and NaBH ₄ (6 g / l) as a reduction bath is exemplified.

In the mixed aqueous solution of an organic acid and a cupric complex used in the spraying treatment, the organic acid may be, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, acrylic acid, crotonic acid, or oxalic acid. Acid, malonic acid,
Examples include succinic acid, glutaric acid, maleic acid, benzoic acid, glycolic acid, lactic acid, malic acid, and sulfamic acid. These may be used alone or in combination of two or more. In the mixed solution, the content of the organic acid is desirably 0.1 to 30% by weight. This is because the solubility of the oxidized copper can be maintained and the stability of the catalyst can be ensured.

As the cupric complex, a cupric complex of an azole is preferred. This cupric complex of azoles is
It acts as an oxidizing agent that oxidizes metallic copper and the like. Examples of the azoles include diazole, triazole, tetrazole and the like. Among these, imidazole, 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, and 2-undecylimidazole are desirable. In the etching solution, the content of the cupric complex is desirably 1 to 15% by weight. This is because it is excellent in solubility and stability, and can also dissolve noble metals such as Pd constituting the catalyst core.

As a specific method of the plating treatment,
Copper sulfate (1-40 g / l), nickel sulfate (0.1-
6.0 g / l), citric acid (10-20 g / l), sodium hypophosphite (10-100 g / l), boric acid (1
0 to 40 g / l) and a surfactant (Surfynol 465, manufactured by Nissin Chemical Industry Co., Ltd.) (0.01 to 10 g / l)
And a method in which electroless plating is performed in an electroless plating bath having a pH of 9 and the like.

(3) Next, a layer of a resin composition is formed on the substrate on which the conductor circuit is formed, and the layer of the resin composition is
An interlayer resin insulating layer is formed by forming a via hole opening and, if necessary, a through hole. Examples of the material of the interlayer resin insulating layer include a resin composition for forming a roughened surface, a polyphenylene ether resin, a polyolefin resin, a fluororesin, and a thermoplastic elastomer. The resin composition layer may be molded by applying an uncured resin,
Alternatively, an uncured resin film may be formed by thermocompression bonding. Further, a resin film in which a metal layer such as a copper foil is formed on one surface of an uncured resin film may be attached.

As the resin composition for forming a roughened surface, for example, particles soluble in an acid or an oxidizing agent (hereinafter referred to as “soluble particles”) are hardly soluble in an acid or an oxidizing agent (hereinafter referred to as a “slightly soluble resin”). And those dispersed therein. Note that the terms "sparingly soluble" and "soluble" are referred to as "soluble" for convenience when a substance having a relatively high dissolution rate is immersed in the same roughening solution for the same time, and the relative dissolution rate is relatively low. The slower one is called "poorly soluble" for convenience.

Examples of the soluble particles include resin particles soluble in an acid or an oxidizing agent (hereinafter referred to as “soluble resin particles”), inorganic particles soluble in an acid or oxidizing agent (hereinafter referred to as “soluble inorganic particles”), and acid or oxidizing agents. Soluble metal particles (hereinafter referred to as “soluble metal particles”) and the like. These soluble particles may be used alone or in combination of two or more.

The shape (particle size, etc.) of the soluble particles is not particularly limited, but (a) soluble particles having an average particle size of 10 μm or less, and (b) aggregation of soluble particles having an average particle size of 2 μm or less. Particles, (c) average particle size is 2 to 10 μm
(D) either a heat-resistant resin powder or an inorganic powder having an average particle size of 2 μm or less on the surface of the soluble particles having an average particle size of 2 to 10 μm; (E) a mixture of soluble particles having an average particle size of 0.1 to 0.8 μm and soluble particles having an average particle size of more than 0.8 μm and less than 2 μm, ) Average particle size is 0.1 to 1.0 μm
It is desirable to use soluble particles of This is because these can form a more complicated anchor.

Examples of the soluble resin particles include those made of a thermosetting resin, a thermoplastic resin, and the like. When immersed in a solution containing an acid or an oxidizing agent, the soluble resin particles have a higher dissolution rate than the hardly soluble resin. If it is, there is no particular limitation. Specific examples of the soluble resin particles include, for example, those made of epoxy resin, phenol resin, polyimide resin, polyphenylene resin, polyolefin resin, fluororesin, amino resin (melamine resin, urea resin, guanamine resin), and the like. These resins may be composed of one kind or a mixture of two or more kinds of resins.

As the soluble resin particles, resin particles made of rubber can also be used. Examples of the rubber include polybutadiene rubber, various modified polybutadiene rubbers such as epoxy-modified, urethane-modified, (meth) acrylonitrile-modified, and (meth) acrylonitrile-butadiene rubber containing a carboxyl group. By using these rubbers, the soluble resin particles are easily dissolved in an acid or an oxidizing agent. In other words, when dissolving the soluble resin particles using an acid, an acid other than a strong acid can be dissolved, and when dissolving the soluble resin particles using an oxidizing agent, permanganese having a relatively weak oxidizing power is used. It can also dissolve in acids. Even when chromic acid is used, it can be dissolved at a low concentration. for that reason,
Acid or oxidizing agent does not remain on the resin surface, and as described later, when a catalyst such as palladium chloride is applied after forming a roughened surface, the catalyst is not applied or the catalyst is oxidized. There is no.

Examples of the soluble inorganic particles include particles made of at least one selected from the group consisting of aluminum compounds, calcium compounds, potassium compounds, magnesium compounds and silicon compounds.

Examples of the aluminum compound include alumina and aluminum hydroxide, and examples of the calcium compound include calcium carbonate and
Calcium hydroxide and the like, as the potassium compound, for example, potassium carbonate and the like, as the magnesium compound, for example, magnesia, dolomite, basic magnesium carbonate and the like, as the silicon compound, For example, silica, zeolite and the like can be mentioned. These may be used alone or in combination of two or more.

Examples of the soluble metal particles include, for example,
Copper, nickel, iron, zinc, lead, gold, silver, aluminum,
Examples include particles made of at least one selected from the group consisting of magnesium, calcium, and silicon. These soluble metal particles may have a surface layer coated with a resin or the like in order to ensure insulation.

When two or more of the above-mentioned soluble particles are used in combination, the combination of the two types of soluble particles to be mixed is preferably a combination of resin particles and inorganic particles. Both have low conductivity, so the insulation of the resin film can be ensured, and the thermal expansion can be easily adjusted with the poorly soluble resin, and cracks occur in the interlayer resin insulation layer formed using the resin film. This is because no peeling occurs between the interlayer resin insulating layer and the conductor circuit.

The hardly soluble resin is not particularly limited as long as it can maintain the shape of the roughened surface when the roughened surface is formed on the interlayer resin insulating layer using an acid or an oxidizing agent. Examples thereof include thermosetting resins, thermoplastic resins, and composites thereof. Further, a photosensitive resin obtained by imparting photosensitivity to these resins may be used. Among these, those containing a thermosetting resin are desirable. Thereby, the shape of the roughened surface can be maintained even by the plating solution or various heat treatments.

Examples of the thermosetting resin include an epoxy resin, a phenol resin, and a polyimide resin. Examples of the photosensitive resin include those obtained by subjecting methacrylic acid, acrylic acid, or the like to an acrylate reaction with a thermosetting group. In particular, an acrylated epoxy resin is desirable. Among these, an epoxy resin having two or more epoxy groups in one molecule is more desirable. Not only can the above-described roughened surface be formed, but also excellent in heat resistance, etc., even under heat cycle conditions, stress concentration does not occur in the metal layer, and peeling of the metal layer does not easily occur. Because.

Examples of the epoxy resin include cresol novolak epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, phenol novolak epoxy resin, alkylphenol novolak epoxy resin, biphenol F epoxy resin, and naphthalene epoxy resin. Resin, dicyclopentadiene type epoxy resin, epoxidized product of condensate of phenols and aromatic aldehyde having phenolic hydroxyl group,
Triglycidyl isocyanurate, alicyclic epoxy resin and the like. These may be used alone or in combination of two or more. Thereby, it becomes excellent in heat resistance and the like.

Examples of the thermoplastic resin include polyether sulfone (PES) and polysulfone (PS).
F), polyphenylene sulfone (PPS), polyphenylene sulfide (PPES), polyphenylene ether (PPE), polyetherimide (PI), phenoxy resin, fluororesin and the like.

The mixing ratio of the above-mentioned thermosetting resin and thermoplastic resin is as follows: thermosetting resin / thermoplastic resin = 95/5 to 50
/ 50 is desirable. This is because a high toughness value can be secured without impairing the heat resistance.

The mixing weight ratio of the above-mentioned soluble particles is preferably 5 to 50% by weight based on the solid content of the hardly-soluble resin.
40% by weight is more desirable.

When the interlayer resin insulating layer is formed using an uncured resin film, it is desirable that the soluble particles in the resin film are substantially uniformly dispersed in the poorly soluble resin. It is possible to form a roughened surface with unevenness of uniform roughness, and even if via holes and through holes are formed in the resin film, it is possible to secure the adhesion of the metal layer of the conductor circuit formed thereon. Because you can. Alternatively, a resin film containing soluble particles only in the surface layer forming the roughened surface may be used. Thereby,
Since the portions other than the surface layer of the resin film are not exposed to the acid or the oxidizing agent, the insulation between the conductor circuits via the interlayer resin insulating layer is reliably maintained.

In the above resin film, the amount of the soluble particles dispersed in the poorly soluble resin is preferably 3 to 40% by weight based on the resin film. If the amount of the soluble particles is less than 3% by weight, it may not be possible to form a roughened surface having desired irregularities. If the amount exceeds 40% by weight, the soluble particles may be dissolved using an acid or an oxidizing agent. In addition, the resin film may be melted to a deep portion, and the insulation between the conductor circuits via the interlayer resin insulating layer formed using the resin film may not be maintained, which may cause a short circuit.

The resin film may contain a curing agent, a solvent, other components, and the like, if necessary, in addition to the soluble particles and the hardly-soluble resin.

The polyphenylene ether resin is not particularly restricted but includes, for example, polyphenylene oxide (PPO), polyphenylene ether (PPE) and the like. Examples of the polyolefin-based resin include polyethylene, polypropylene, polyisobutylene, polybutadiene, polyisoprene, cycloolefin-based resins, and copolymers of these resins. Among them, the dielectric constant and the dielectric loss tangent are low, and GHz
Even when a high frequency signal in a band is used, a cycloolefin-based resin is preferable because signal delay and signal error hardly occur, and further, mechanical properties such as rigidity are excellent.

As the above cycloolefin resin, 2
Homopolymers or copolymers of monomers comprising -norbornene, 5-ethylidene-2-norbornene or derivatives thereof are desirable. As the above derivative, the above 2-
Examples thereof include those in which an amino group for forming a crosslink, a maleic anhydride residue, or a maleic acid-modified one is bonded to a cycloolefin such as norbornene. Examples of monomers for synthesizing the copolymer include ethylene and propylene.

The cycloolefin resin may be a mixture of two or more of the above resins, or may contain a resin other than the cycloolefin resin. When the cycloolefin resin is a copolymer, it may be a block copolymer or a random copolymer.

The cycloolefin resin is preferably a thermosetting cycloolefin resin.
This is because by performing the heating to form the crosslinks, the rigidity is further increased and the mechanical properties are improved. The glass transition temperature (Tg) of the cycloolefin resin is 13
Desirably, the temperature is 0 to 200 ° C.

As the above cycloolefin-based resin, those already formed as a resin sheet (film) may be used, and a monomer or a low molecular weight polymer having a constant molecular weight may be used in a solvent such as xylene or cyclohexane. It may be in the state of an uncured solution dispersed in. In the case of a resin sheet, a so-called RCC (RESIN COATE
D COPER: resin-coated copper foil).

The cycloolefin resin may not contain a filler or the like, or may contain a flame retardant such as aluminum hydroxide, magnesium hydroxide, or a phosphate.

The fluororesin includes, for example, ethyl / tetrafluoroethylene copolymer resin (ETFE), polychlorotrifluoroethylene (PCTFE) and the like.

The thermoplastic elastomer resin is not particularly restricted but includes, for example, styrene-based thermoplastic elastomers, olefin-based thermoplastic elastomers, urethane-based thermoplastic elastomers, polyester-based thermoplastic elastomers, polyamide-based thermoplastic elastomers, -Polybutadiene-based thermoplastic elastomers, PVC-based thermoplastic elastomers, fluorine-based thermoplastic elastomers, and the like. Among these, olefin-based thermoplastic elastomers and fluorine-based thermoplastic elastomers are desirable from the viewpoint of excellent electrical properties.

The resin used for forming these interlayer resin insulation layers preferably contains the above-mentioned P-atom-containing epoxy resin. Not only solder resist layer,
Since the interlayer resin insulating layer also contains the P-atom-containing epoxy resin, the flame retardancy of the multilayer printed wiring board is further improved.

When the interlayer resin insulating layer is formed by attaching the above resin film, the interlayer resin insulating layer is formed using a device such as a vacuum laminator under reduced pressure or vacuum under a pressure of 2.0 to 10 kgf / kg. pressure of cm ^2,
It is desirable to perform pressure bonding at a temperature of 60 to 120 ° C., and then heat-curing the resin film. The heat curing may be performed after forming a via hole opening and a through hole described later.

After forming the resin composition layer, an interlayer resin insulating layer is formed by forming a via hole opening and, if necessary, a through hole in the resin composition layer.
The via hole opening is formed by laser processing or the like. In the case where a layer of a resin composition made of a photosensitive resin is formed, an opening for a via hole may be provided by performing exposure and development treatments. At this time, as a laser beam used, for example, a carbon dioxide (CO ₂ ) laser,
An ultraviolet laser, an excimer laser and the like can be mentioned, and among these, an excimer laser and a short-pulse carbon dioxide laser are desirable.

The excimer laser can form a large number of via hole openings at a time by using a mask or the like in which a through hole is formed in a portion where a via hole opening is formed, as described later. This is because the short-pulse carbon dioxide laser has less resin residue in the opening and less damage to the resin around the opening.

It is desirable to use a hologram type excimer laser among the excimer lasers. The hologram method is a method of irradiating a target object with a laser beam through a hologram, a condensing lens, a laser mask, a transfer lens, and the like. Can be efficiently formed.

When a carbon dioxide laser is used, the pulse interval is desirably 10 ⁻⁴ to 10 ⁻⁸ seconds. The time for irradiating the laser for forming the opening is preferably 10 to 500 μsec. Further, the through-hole of the mask in which the through-hole is formed in the portion where the via-hole opening is formed needs to be a perfect circle in order to make the spot shape of the laser beam a perfect circle, and the diameter of the through-hole is ,
About 0.1 to 2 mm is desirable.

By irradiating a laser beam through an optical lens and a mask, a large number of via hole openings can be formed at once. This is because a plurality of portions can be simultaneously irradiated with laser light having the same intensity and the same irradiation intensity through the optical system lens and the mask.

When an opening is formed by a laser beam, particularly when a carbon dioxide gas laser is used, desmearing is preferably performed. The desmear treatment can be performed using an oxidizing agent composed of an aqueous solution such as chromic acid and permanganate. Alternatively, the treatment may be performed using oxygen plasma, a mixed plasma of CF ₄ and oxygen, corona discharge, or the like. The surface can also be modified by irradiating ultraviolet rays using a low-pressure mercury lamp. When a through-hole is formed in the substrate on which the layer of the resin composition is formed, the diameter is 50 to 300.
A through hole is formed using a μm drill, laser light, or the like.

(4) Next, the surface of the interlayer resin insulating layer including the inner wall of the opening for the via hole and the inner wall of the through hole when the through hole is formed in the above step are roughened with an acid or an oxidizing agent. To form a surface. Examples of the acid include sulfuric acid, nitric acid, hydrochloric acid,
Examples of the oxidizing agent include phosphoric acid, formic acid, and the like. Examples of the oxidizing agent include permanganates such as chromic acid, chromic sulfuric acid, and sodium permanganate.

Thereafter, when the roughened surface is formed by using an acid, an aqueous solution of an alkali or the like is used, and when the roughened surface is formed by using an oxidizing agent, a neutralizing solution is used. Neutralizes the inside of the through hole. By this operation, the acid and the oxidizing agent are removed so that the next step is not affected. The average roughness Rz of the roughened surface formed in this step is 0.1 to 5 μm.
m is desirable.

(5) Next, a catalyst is applied to the formed roughened surface, if necessary. Examples of the catalyst include palladium chloride. At this time, in order to reliably apply the catalyst, a dry treatment such as a plasma treatment with oxygen, nitrogen or the like or a corona treatment is performed to remove a residue of an acid or an oxidizing agent and modify the surface of the interlayer resin insulating layer. By doing so, the catalyst can be reliably applied, the metal can be deposited during electroless plating, and the adhesion of the electroless plating layer to the interlayer resin insulating layer can be improved. In particular, the bottom surface of the via hole opening can be improved. In the above, a great effect can be obtained.

(6) Next, a thin-film conductor layer made of tin, zinc, copper, nickel, cobalt, thallium, lead or the like is formed on the formed interlayer resin insulation layer by electroless plating, sputtering, or the like, if necessary. . The above-mentioned thin film conductor layer may be a single layer, or may be composed of two or more layers. Among these, a thin film conductor layer made of copper, copper, and nickel is desirable in consideration of electrical characteristics, economy, and the like. When the through hole is formed in the step (3), a through-hole may be formed by forming a thin film conductor layer made of metal also on the inner wall surface of the through hole in this step.

When a through hole is formed in the step (6), it is desirable to perform the following processing steps. That is, the surface of the electroless plating layer and the inner wall of the through hole are subjected to blackening (oxidation) -reduction treatment, spray treatment with a mixed aqueous solution of an organic acid and a cupric complex, treatment with Cu-Ni-P needle-like alloy plating, and the like. To perform a roughening process. Thereafter, the inside of the through-hole is further filled with a resin filler or the like, and then the surface layer of the resin filler and the surface of the electroless plating layer are flattened by a polishing treatment method such as buffing. Further, by performing electroless plating and forming an electroless plating layer on the thin film conductor layer made of a metal already formed and the surface layer of the resin filler, a cover plating layer is formed on the through hole.

(7) Next, a plating resist is formed on a part of the interlayer resin insulating layer using a dry film, and then electroplating is performed using the thin film conductor layer as a plating lead to form the plating resist. An electroplating layer thicker than the thickness of the plating resist is formed in the portion. It is desirable to use copper plating as the electroplating. At this time, the via hole opening may be filled with electroplating to form a field via structure, and after filling the via hole opening with a conductive paste or the like, a lid plating layer may be formed thereon to form a field via structure. Good. By forming a field via structure, a via hole can be provided immediately above the via hole.

(8) After forming the electroplating layer, the plating resist is peeled off, and the thin film conductor layer made of the metal existing under the plating resist is removed by etching to form an independent conductor circuit. It is desirable to use copper plating as the electroplating. As an etchant, for example, a sulfuric acid-hydrogen peroxide aqueous solution, ammonium persulfate, sodium persulfate, a persulfate aqueous solution such as potassium persulfate,
An aqueous solution of ferric chloride, cupric chloride, or the like, hydrochloric acid, nitric acid, hot dilute sulfuric acid, or the like can be given. Further, a roughened surface may be formed at the same time as etching between conductor circuits using an etching solution containing the above-described cupric complex and an organic acid. Further, if necessary, the catalyst on the interlayer resin insulating layer may be removed using an acid or an oxidizing agent. By removing the catalyst, the metal such as palladium used for the catalyst disappears, so that a decrease in the electrical characteristics can be prevented.

(9) Thereafter, if necessary, the steps (3) to (8) are repeated. If it is necessary to form a roughened surface on the outermost conductor circuit, the above-described roughened surface is formed. A conductor circuit having a roughened surface is formed by using a forming method.

(10) Next, the above-mentioned solder resist layer is formed on the substrate surface including the outermost conductive circuit. As described above, the solder resist layer is formed by applying a solder resist composition containing the P-atom-containing epoxy resin by a roll coater method or the like, or after forming a resin film of the solder resist composition, After thermocompression bonding, an opening process such as exposure, development, or laser processing is performed, and a hardening process is performed.

When the opening is formed by exposure and development, the solder resist layer is formed of the P
By using the same resin as that usually used except for the atom-containing epoxy resin, an opening having a desired shape can be formed in the layer of the solder resist composition with the same ease as in the related art.

In the case where the opening is formed by laser treatment, the opening having a desired shape can be formed because the resin contains a P atom-containing epoxy resin. Normally, when an opening is formed by laser irradiation, the resin around the laser irradiation site is burned by the heat of the laser irradiation, so that the shape of the inner wall of the opening does not have a smooth shape and has uneven unevenness. Become. However, since the solder resist layer of the multilayer printed wiring board of the present invention has flame retardancy due to containing a P atom-containing epoxy resin,
The resin around the laser irradiation site does not burn due to the irradiation heat of the laser, and the shape of the inner wall of the formed opening is smooth and the desired shape is obtained.

Further, since the resin around the laser irradiation site is not burned by the laser irradiation heat at the time of laser irradiation, an opening having a desired shape can be formed even when high-energy laser light is irradiated. it can. Therefore, by irradiating high-energy laser light, an opening can be formed in a short time. In particular, when a pulsed laser is used, an opening can be formed in a single shot. In addition,
In the laser treatment, a laser beam or a method of irradiating a laser beam used for forming an opening in the layer of the solder resist composition includes an opening in a dried body of the resin composition layer in order to form an interlayer resin insulating layer. Is formed.

(11) Next, a corrosion-resistant metal layer made of Ni, Au, or the like is formed in the opening of the solder resist layer by plating, sputtering, evaporation, or the like, and then, a solder paste is printed on the IC chip connection surface. Thus, solder bumps are formed, and solder balls, pins, and the like are provided on the external substrate connection surface, thereby completing the manufacture of the printed wiring board. In addition, as a method of arranging the solder balls, pins, and the like, a conventionally known method can be used.

In addition, a plasma treatment with oxygen, carbon tetrachloride, or the like may be performed as needed for a character printing step for forming a product recognition character or the like or for modifying a solder resist layer. Although the above method is based on the semi-additive method, a full additive method may be employed.

[0110]

The present invention will be described in more detail below. Example 1 A. Preparation of Resin Composition for Forming Roughened Surface of Upper Layer (1) A 25% acrylate of cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) is dissolved in diethylene glycol dimethyl ether (DMDG) at a concentration of 80% by weight. 400 parts by weight of the resin solution, photosensitive monomer (Aronix M325, manufactured by Toa Gosei Co., Ltd.) 60
A mixed composition was prepared by placing parts by weight, 5 parts by weight of an antifoaming agent (S-65, manufactured by San Nopco) and 35 parts by weight of N-methylpyrrolidone (NMP) in a container and mixing with stirring.

(2) Polyether sulfone (PES) 8
0 parts by weight, 72 parts by weight of an epoxy resin particle (manufactured by Sanyo Chemical Industries, polymer pole) having an average particle size of 1.0 μm and 31 parts by weight of an epoxy resin particle having an average particle size of 0.5 μm were placed in another container and mixed with stirring. And 257 parts by weight of NMP were further added and stirred and mixed by a bead mill to prepare another mixed composition.

(3) Imidazole curing agent (manufactured by Shikoku Chemicals, Inc.)
2E4MZ-CN), 20 parts by weight of a photopolymerization initiator (benzophenone), 4 parts by weight of a photosensitizer (EAB, manufactured by Ciba Specialty Chemicals) and NMP1
6 parts by weight were placed in another container and mixed by stirring to prepare a mixed composition. And (1), (2) and
The resin composition for forming a roughened surface was obtained by mixing the mixed composition prepared in (3).

B. Preparation of Resin Composition for Forming Lower Surface Roughened Surface (1) Dissolve 25% acrylate of cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., molecular weight: 2500) in diethylene glycol dimethyl ether (DMDG) at a concentration of 80% by weight. 400 parts by weight of the resin solution, photosensitive monomer (Aronix M325, manufactured by Toa Gosei Co., Ltd.) 60
A mixed composition was prepared by placing parts by weight, 5 parts by weight of an antifoaming agent (S-65, manufactured by San Nopco) and 35 parts by weight of N-methylpyrrolidone (NMP) in a container and mixing with stirring.

(2) Polyether sulfone (PES) 8
0 parts by weight and 145 parts by weight of an epoxy resin particle (manufactured by Sanyo Kasei Co., Ltd., polymer pole) having an average particle size of 0.5 μm are placed in another container, mixed with stirring, and further mixed with NMP2.
85 parts by weight were added and mixed by stirring with a bead mill to prepare another mixed composition.

(3) Imidazole curing agent (manufactured by Shikoku Chemicals, Inc.)
2E4MZ-CN), 20 parts by weight of a photopolymerization initiator (benzophenone), 4 parts by weight of a photosensitizer (EAB, manufactured by Ciba Specialty Chemicals) and NMP1
6 parts by weight were placed in another container and mixed by stirring to prepare a mixed composition. And (1), (2) and
The resin composition for forming a roughened surface was obtained by mixing the mixed composition prepared in (3).

C. Preparation of resin filler (1) 100 parts by weight of bisphenol F type epoxy monomer (manufactured by Yuka Shell Co., molecular weight: 310, YL983U),
SiO ₂ spherical particles having an average particle diameter of 1.6 μm and a maximum particle diameter of 15 μm or less (CRS 1101 manufactured by Adtec Co., Ltd.) having a surface coated with a silane coupling agent.
-CE) 170 parts by weight and 1.5 parts by weight of a leveling agent (Perenol S4 manufactured by San Nopco) are placed in a container, and the mixture is stirred and mixed to have a viscosity of 23 to 1 ° C. and 45 to 45 ° C.
A resin filler of 49 Pa · s was prepared. As a curing agent, an imidazole curing agent (2E4MZ manufactured by Shikoku Chemicals Co., Ltd.)
-CN) 6.5 parts by weight.

D. Manufacturing method of printed wiring board (1) Glass epoxy resin or BT with a thickness of 0.8 mm
The starting material was a copper-clad laminate in which 18 μm copper foils 8 were laminated on both sides of a substrate 1 made of (bismaleimide triazine) resin (see FIG. 1A). First, the copper-clad laminate was drilled, subjected to an electroless plating treatment, and etched in a pattern to form a lower conductor circuit 4 and a through hole 9 on both surfaces of the substrate 1.

(2) Through-hole 9 and lower conductor circuit 4
After the substrate on which was formed was washed with water and dried, NaOH (1
0 g / l), NaClO ₂ (40 g / l), Na ₃ PO
₄ A blackening treatment using an aqueous solution containing (16 g / l) as a blackening bath (oxidizing bath), NaOH (19 g / l), NaB
A reduction treatment was performed using an aqueous solution containing H ₄ (5 g / l) as a reduction bath, and roughened surfaces 4 a and 9 a were formed on the entire surface of the lower conductor circuit 4 including the through holes 9 (see FIG. 1 (b)). ).

(3) After preparing the resin filler described in D above, within 24 hours after preparation by the following method, the conductive circuit non-formed portion in the through hole 9 and on one side of the substrate 1 and the conductive circuit A layer of the resin filler 10 was formed on the outer edge portion of No. 4. That is, first, the resin filler was pushed into the through holes using a squeegee, and then dried at 100 ° C. for 20 minutes. Next, a mask having an opening corresponding to the conductive circuit non-forming portion is placed on the substrate, and a layer of the resin filler 10 is formed in the conductive circuit non-forming portion having a concave portion using a squeegee. Drying was performed at 20 ° C. for 20 minutes (see FIG. 1C).

(4) One surface of the substrate after the treatment of (3) is subjected to belt sander polishing using # 600 belt polishing paper (manufactured by Sankyo Rikagaku) to form the surface of the inner layer copper pattern 4 and the through holes 9. Polishing was performed so that the resin filler 10 did not remain on the land surface, and then buffing was performed to remove scratches caused by the belt sander polishing. Such a series of polishing was similarly performed on the other surface of the substrate. Then, at 100 ° C for 1 hour, at 120 ° C for 3 hours, at 150 ° C
For 1 hour and a heat treatment at 180 ° C. for 7 hours to cure the resin filler 10.

In this way, the surface portion of the resin filler 10 formed in the through hole 9 and the portion where the conductor circuit is not formed and the surface of the lower conductor circuit 4 are flattened, and the resin filler 10 and the side surface of the lower conductor circuit 4 are flattened. 4a is firmly adhered through the roughened surface, and the inner wall surface 9a of the through hole 9 and the resin filler 10
Was obtained, thereby obtaining an insulating substrate firmly adhered through the roughened surface (see FIG. 1D). By this step, the resin filler 10
And the surface of the lower conductor circuit 4 are flush with each other.

(5) The substrate is washed with water and acid-degreased, and then soft-etched. Then, an etchant is sprayed on both surfaces of the substrate by spraying, so that the surface of the lower conductive circuit 4 and the land surface of the through hole 9 and the inner wall are formed. Thus, roughened surfaces 4a and 9a were formed on the entire surface of lower conductor circuit 4 (see FIG. 2A). As an etching solution, an etching solution (Mec etch bond, manufactured by Mec Co.) consisting of 10 parts by weight of imidazole copper (II) complex, 7 parts by weight of glycolic acid, and 5 parts by weight of potassium chloride was used.

(6) The resin composition for forming a roughened surface of the above B (viscosity: 1.5 Pa · s) was applied to both surfaces of a substrate by a roll coater, and allowed to stand in a horizontal state for 20 minutes. 3
Drying was performed for 0 minutes to form a roughened surface forming resin layer 2a. Further, the above-mentioned A is formed on the roughened surface forming resin layer 2a.
Is applied using a roll coater and left in a horizontal state for 20 minutes, and then dried at 60 ° C. for 30 minutes to form a roughened surface. The resin layer 2b was formed, and a resin layer for forming a roughened surface having a thickness of 35 μm was formed (see FIG. 2B).

(7) A photomask film on which a black circle having a diameter of 85 μm is printed is brought into close contact with both surfaces of the substrate 1 on which the resin layer for forming a roughened surface has been formed in the above (6), and is 500 mJ / cm by an ultra-high pressure mercury lamp. After exposure at ^two intensities, it was spray-developed with a DMDG solution. Thereafter, the substrate was further exposed to 3000 mJ / cm ² intensity using an ultrahigh pressure mercury lamp,
Heat treatment at 0 ° C. for 1 hour, 120 ° C. for 1 hour, and 150 ° C. for 3 hours, and a 35 μm thick interlayer resin having a via hole opening 6 of 85 μm in diameter and excellent in dimensional accuracy equivalent to a photomask film. An insulating layer 2 was formed (FIG. 2
(C)).

(8) The substrate on which the via hole opening 6 was formed was placed in a 70 ° C. solution containing 800 g / l of chromic acid.
For 2 minutes, the surface of the interlayer resin insulation layer 2 was roughened (3 μm depth) by dissolving and removing the epoxy resin particles present on the surface of the interlayer resin insulation layer 2 (see FIG. 2D).

(9) Next, the substrate after the above treatment was immersed in a neutralizing solution (manufactured by Shipley) and washed with water. Further, by applying a palladium catalyst (manufactured by Atotech) to the surface of the substrate subjected to the surface roughening treatment, catalyst nuclei were attached to the surface of the interlayer resin insulating layer 2 and the inner wall surface of the via hole opening 6.

(10) Next, the substrate was immersed in an electroless copper plating aqueous solution having the following composition to form an electroless copper plating layer 12 having a thickness of 0.8 μm on the entire rough surface (FIG. 3A )reference). [Electroless plating aqueous solution] NiSO ₄ 0.003 mol / l tartaric acid 0.200 mol / l copper sulfate 0.030 mol / l HCHO 0.050 mol / l NaOH 0.100 mol / l α, α'-bipyridyl 40 mg / l Polyethylene glycol (PEG) 0.10 g / l [Electroless plating conditions] 40 minutes at a liquid temperature of 35 ° C

(11) Next, a commercially available photosensitive dry film is attached to the electroless copper plating layer 12, and a mask is placed thereon.
Exposure was performed at 100 mJ / cm ² , and development treatment was performed with a 0.8% aqueous sodium carbonate solution to provide a plating resist 3 having a thickness of 25 μm (see FIG. 3B).

(12) Next, the substrate was washed with water at 50 ° C., degreased, washed with water at 25 ° C., further washed with sulfuric acid, and then subjected to electrolytic copper plating under the following conditions. The layer 13 was formed (see FIG. 4C). [Aqueous electrolytic plating solution] Sulfuric acid 2.24 mol / l Copper sulfate 0.26 mol / l Additive 19.5 ml / l (Acapec Japan, Capparaside GL) [Electroplating conditions] Current density 1 A / dm ² hours 65 minutes temperature 22 ± 2 degrees

(13) Further, the plating resist 3 is coated with 5% KO
After removing with H, the electroless plating layer 12 under the plating resist 3 is dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide to form an independent conductor circuit 5 (including the via hole 7). (See FIG. 3D).

(14) By repeating the above steps (5) to (13), a conductor circuit of a further upper layer was formed, and a multilayer wiring board was obtained (see FIGS. 4A to 5B). .

(15) Next, a solder resist composition containing a P atom-containing epoxy resin was prepared by the following method.
In the above general formula (1), P is dissolved in diethylene glycol dimethyl ether (DMDG) to a concentration of 60% by weight, and X ¹ and X ² are O (oxygen).
Photosensitizing oligomer (molecular weight: 4000) 4 in which 50% of epoxy groups of an atom-containing epoxy resin are acrylated
6.67 parts by weight of 80 dissolved in methyl ethyl ketone
6.67 parts by weight of a bisphenol A type epoxy resin in weight%, an imidazole curing agent (2E4MZ- manufactured by Shikoku Chemicals Co., Ltd.)
CN) 1.6 parts by weight, 4.5 parts by weight of a photosensitive monomer, bifunctional acrylic monomer (R604, manufactured by Nippon Kayaku Co., Ltd.), and similarly polyvalent acrylic monomer (Kyoei Chemical Co., DP
E6A) 1.5 parts by weight of a leveling agent composed of an acrylate polymer (manufactured by Kyoei Chemical Co., Ltd., Polyflow No. 7)
5) 0.36 parts by weight was placed in a container, stirred and mixed to prepare a mixed composition, and 2.0 parts by weight of benzophenone (manufactured by Kanto Chemical Co., Ltd.) as a photopolymerization initiator was added to the mixed composition
Michler's ketone (manufactured by Kanto Chemical Co.) 0.2 as a photosensitizer
By adding 0.6 parts by weight of DMDG and 0.6 parts by weight of DMDG, a solder resist composition having a viscosity adjusted to 1.4 ± 0.3 Pa · s at 25 ° C. was prepared. The viscosity was measured with a B-type viscometer (DVL-B type, manufactured by Tokyo Keiki Co., Ltd.) when the rotor No. was 60 rpm. Rotor N at 4,6 rpm
o. According to 3.

(16) Next, the above-mentioned solder resist composition is applied to both sides of the multilayer wiring board in a thickness of 20 μm,
After performing a drying process under the conditions of 20 ° C. for 20 minutes and 70 ° C. for 20 minutes, a 5 mm-thick photomask on which a pattern of the solder resist opening is drawn is brought into close contact with the layer of the solder resist composition to 900 mJ / cm. The substrate was exposed to ultraviolet light of No. ² and subjected to pure water development to form an opening having a diameter of 125 μm. Then, under the condition of 3000 mJ / cm ² , U
V cure, 80 ° C for 1 hour, 100 ° C for 1 hour, 12
Heat treatment is performed at 0 ° C. for 1 hour and 150 ° C. for 3 hours to cure the layer of the solder resist composition,
The solder resist layer 14 having an opening and a thickness of 25 μm was formed.

(17) Next, the substrate on which the solder resist layer 14 was formed was coated with nickel chloride (30 g / l), sodium hypophosphite (10 g / l), and sodium citrate (10 g / l).
g / l) in the electroless nickel plating solution with pH = 5.
This was immersed for 0 minutes to form a nickel plating layer 15 having a thickness of 5 μm in the opening. Further, the substrate was subjected to potassium gold cyanide (2 g / l), ammonium chloride (75 g / l),
It was immersed in an electroless plating solution containing sodium citrate (50 g / l) and sodium hypophosphite (10 g / l) at a temperature of 93 ° C. for 23 seconds to form a 0.03 μm thick nickel plating layer 15 on the nickel plating layer 15. A gold plating layer 16 was formed.

(18) Thereafter, a solder paste is printed in the openings of the solder resist layer 14 and reflowed at 200 ° C. to form solder bumps (solder bodies) 17.
A multilayer wiring printed board having the solder bumps 17 was manufactured (see FIG. 5C).

Example 2 A. Preparation of Resin Film for Interlayer Resin Insulation Layer Bisphenol A type epoxy resin (Epoxy equivalent 46
9. Yuka Shell Epoxy Epicoat 1001) 3
0 parts by weight, 40 parts by weight of a cresol novolak type epoxy resin (epoxy equivalent: 215, Epichron N-673 manufactured by Dainippon Ink and Chemicals, Inc.), a triazine structure-containing phenol novolak resin (phenolic hydroxyl group equivalent: 120,
FENOLITE KA-705 manufactured by Dainippon Ink and Chemicals, Inc.
2) 30 parts by weight were dissolved in 20 parts by weight of ethylene glycol acetate and 20 parts by weight of solvent naphtha while being heated and stirred, and epoxidized polybutadiene rubber (Denalex R-45EPT manufactured by Nagase Kasei Kogyo Co., Ltd.) was added thereto.
15 parts by weight, 1.5 parts by weight of a crushed product of 2-phenyl-4,5-bis (hydroxymethyl) imidazole, 2 parts by weight of finely divided silica, and 0.5 part by weight of a silicon-based antifoaming agent are added, and an epoxy resin composition is added. Was prepared. The resulting epoxy resin composition is applied on a 38 μm-thick PET film using a roll coater so that the thickness after drying becomes 50 μm, and then dried at 80 to 120 ° C. for 10 minutes to form an interlayer resin. A resin film for an insulating layer was produced.

B. Manufacturing method of printed wiring board (1) 1.0 mm thick glass epoxy resin or BT
A starting material was a copper-clad laminate in which 18 μm copper foils 8 were laminated on both sides of a substrate 1 made of (bismaleimide triazine) resin (see FIG. 6A). First, the copper-clad laminate was etched in a pattern to form a lower conductive circuit 4 on both surfaces of the substrate 1.

(2) The above substrate was washed with water and acid degreased, and then soft-etched. Then, an etching solution was sprayed on both surfaces of the substrate by spraying, and the etching solution was conveyed to the substrate surface by conveyance rolls. Is etched to form a roughened surface 4a on the entire surface of the lower conductive circuit 4 (see FIG. 6B). As an etchant,
An etching solution (Mec etch bond, manufactured by Mec) comprising 10 parts by weight of imidazole copper (II) complex, 7 parts by weight of glycolic acid, and 5 parts by weight of potassium chloride was used.

(3) On both sides of the substrate, a resin film for an interlayer resin insulating layer slightly larger than the substrate prepared in A was placed on the substrate, and the pressure was 4 kgf / cm ² , the temperature was 80 ° C., and the compression time was 10 seconds. After temporary compression and cutting, the interlayer resin insulating layer 2 was formed by further applying a vacuum laminator under the following conditions (see FIG. 6C). That is, the resin film for the interlayer resin insulation layer is placed on the substrate,
Vacuum degree 0.5 Torr, pressure 4 kgf / cm ² , temperature 8
This was completely press-bonded at 0 ° C. for 60 seconds, and then thermally cured at 170 ° C. for 30 minutes.

(4) Next, a CO ₂ gas laser having a wavelength of 10.4 μm was used to form a beam having a beam diameter of 4.0 through a mask having a through hole having a thickness of 1.2 mm formed on the interlayer resin insulating layer 2.
The via hole opening 6 having a diameter of 80 μm was formed in the interlayer resin insulating layer 2 under the conditions of mm, top hat mode, pulse width 8.0 μsec, diameter of the through hole of the mask 1.0 mm, and one shot. Further, the substrate on which the interlayer resin insulating layer 2 was formed was drilled to form a through hole 18.
(D)).

(5) The substrate in which the via hole openings 6 and the through holes 18 were formed was immersed in a solution containing 60 g / l of permanganic acid at 80 ° C. for 10 minutes to form an interlayer resin insulating layer 2.
The surface of the interlayer resin insulating layer 2 was roughened by dissolving and removing the epoxy resin particles present on the surface of FIG.
(A)). Furthermore, surface roughening treatment (roughening depth 6 μm)
Palladium catalyst (made by Atotech) on the surface of the substrate
The catalyst nuclei were attached to the surfaces of the interlayer resin insulating layer 2 and the through holes 18 and the inner wall surfaces 6 of the via hole openings.

(6) Next, the substrate is immersed in an electroless copper plating aqueous solution having the following composition, and has a thickness of 0.6 to 3.
A 0 μm electroless copper plating film 12a was formed (FIG. 7).
(B)). [Electroless plating aqueous solution] NiSO ₄ 0.003 mol / l tartaric acid 0.200 mol / l copper sulfate 0.030 mol / l HCHO 0.050 mol / l NaOH 0.100 mol / l α, α'-bipyridyl 40 mg / l Polyethylene glycol (PEG) 0.10 g / l [Electroless plating conditions] 40 minutes at a liquid temperature of 35 ° C

(7) The substrate on which the electroless plating film 12a was formed was washed with water and dried, and then NaOH (10 g / l), N
aClO ₂ (40 g / l), Na ₃ PO ₄ (6 g / l)
Blackening to blackening bath (oxidizing bath) an aqueous solution containing, and, NaOH (10g / l), NaBH 4 (6g / l)
A reduction treatment was performed using an aqueous solution containing Pb as a reduction bath to form a roughened surface on the entire surface of the electroless plating film 12a.

(8) After preparing the resin filler described in B above, the resin filler 10 was filled in the through hole 29 within 24 hours after the preparation by the following method. That is,
After the resin filler was pushed into the through hole 29 using a squeegee, it was dried at 100 ° C. for 20 minutes. After the drying, buffing was performed to flatten the surface of the electroless plating film 12a and the surface layer portion 10a of the resin filler. Next, at 100 ° C. for 1 hour, at 120 ° C. for 3 hours,
Heat treatment was performed at 150 ° C. for 1 hour and at 180 ° C. for 7 hours to cure the resin filler 10 (see FIG. 7C).

(9) Next, a palladium catalyst (manufactured by Atotech Co.) was applied to the surface layer 10a of the resin filler, whereby catalyst nuclei were attached to the surface layer 10a of the resin filler.
Further, electroless plating is performed under the same conditions as in (6) above,
On the electroless plating film 12a formed in the above (6) and the surface portion 10a of the resin filler, a thickness of 0.6 to 3.0 μm is further added.
m of the electroless plating film 12b was formed (see FIG. 7D). By this step, a cover plating layer could be formed on the through hole 29.

(10) A commercially available photosensitive dry film is stuck on the electroless copper plating film 12b, and a mask is placed thereon.
Exposure was performed at 0 mJ / cm ² , and development was performed with a 0.8% aqueous sodium carbonate solution to provide a plating resist 3 having a thickness of 30 μm (see FIG. 8A).

(11) Next, the substrate was washed with water at 50 ° C., degreased, washed with water at 25 ° C., further washed with sulfuric acid, and then subjected to electrolytic copper plating under the following conditions to a thickness of 20 μm. Was formed (see FIG. 8B). [Electroplating aqueous solution] sulfuric acid 2.24 mol / l copper sulfate 0.26 mol / l additive 19.5 ml / l (manufactured by Atotech Japan, Capparaside HL) [electroplating conditions] current density 1 A / dm ² hours 65 minutes Temperature 22 ± 2 ℃

(12) After removing and removing the plating resist 3 with 5% NaOH, the electroless plating films 12a and 12b under the plating resist 3 are dissolved and removed by etching with a mixed solution of sulfuric acid and hydrogen peroxide. A conductor circuit (including the via hole 7) 5 having a thickness of 18 μm including the electroless copper plating film 12 and the electrolytic copper plating film 13 was formed (see FIG. 8C).

(13) The same treatment as in (5) was performed, and a roughened surface was formed with an etching solution containing a cupric complex and an organic acid (see FIG. 8D).

(14) By repeating the above steps (6) to (13), a conductor circuit of a further upper layer was formed, and a multilayer wiring board was obtained (see FIGS. 9 (a) to 10 (a)). .

(15) Next, a P atom-containing epoxy resin is contained
A solder resist composition was prepared by the following method.
Diethylene glycol dimethyl ether (DMDG)
Cresol dissolved to a concentration of 60% by weight
50% epoxy group of novolak epoxy resin
Oligomerized photosensitizer (molecular weight: 4000)
8 dissolved in 46.67 parts by weight of methyl ethyl ketone
In the above general formula (2) at 0% by weight, X ^Three Is a single bond
5. a P atom-containing epoxy resin in which R is a butyl group;
67 parts by weight, imidazole curing agent (Shikoku Chemicals, 2E
4MZ-CN) 1.6 parts by weight, photosensitive monomer 2
3. Functional acrylic monomer (Nippon Kayaku Co., Ltd., R604)
5 parts by weight, also polyvalent acrylic monomer (Kyoei Chemical Co., Ltd.)
DPE6A) 1.5 parts by weight, acrylic acid ester
Leveling agent consisting of compound (Polyflow, manufactured by Kyoei Chemical Co., Ltd.)
No. 75) Place 0.36 parts by weight in a container, stir and mix
To prepare a mixed composition,
Benzophenone (manufactured by Kanto Chemical Co.) 2.0 as a coalescence initiator
Parts by weight, Michler's ketone (Kanto Chemical Co., Ltd.)
0.2 parts by weight and 0.6 parts by weight of DMDG
Adjusts the viscosity to 1.4 ± 0.3 Pa · s at 25 ° C
The prepared solder resist composition was prepared.

(16) Next, the above-mentioned solder resist composition is applied to both sides of the multilayer wiring board in a thickness of 20 μm.
After performing a drying process under the conditions of 20 ° C. for 20 minutes and 70 ° C. for 20 minutes, a 5 mm-thick photomask on which a pattern of the solder resist opening is drawn is brought into close contact with the layer of the solder resist composition to 900 mJ / cm. The resultant was exposed to ultraviolet light of No. ² and subjected to pure water development to form an opening having a diameter of 125 μm. Then, under the condition of 3000 mJ / cm ² , U
V cure, 80 ° C for 1 hour, 100 ° C for 1 hour, 12
Heat treatment is performed at 0 ° C. for 1 hour and 150 ° C. for 3 hours to cure the layer of the solder resist composition,
The solder resist layer 14 having an opening and a thickness of 25 μm was formed.

(17) Next, the substrate on which the solder resist layer 14 was formed was coated with nickel chloride (2.3 × 10 ^-1 mol / mol).
l), sodium hypophosphite (2.8 × 10 ⁻¹ mol /
l), sodium citrate (1.6 × 10 ⁻¹ mol /
2) in the electroless nickel plating solution having pH = 4.5 containing l)
This was immersed for 0 minutes to form a nickel plating layer 15 having a thickness of 5 μm in the opening. Furthermore, the substrate gold potassium cyanide ^{(7.6 × 10 -3 mol / l} ), ammonium chloride ^{(1.9 × 10 -1 mol / l} ), sodium citrate (1.2 × 10 ^-1 mol / l), immersed in an electroless gold plating solution containing sodium hypophosphite (1.7 × 10 ^-1 mol / l) for 7.5 minutes at 80 ° C. A gold plating layer 16 of 0.03 μm was formed.

(18) Thereafter, a solder paste containing tin-lead is printed on the opening of the solder resist layer 14 on the surface of the substrate on which the IC chip is to be mounted, and the opening of the solder resist layer 14 on the other surface is further printed. A solder paste containing tin-antimony is printed on the solder paste, pins are placed on the solder paste, and reflow is performed at 200 ° C. to form solder bumps (solder bodies) 17 on the surface on which the IC chip is placed. PGA was formed on the other surface, and a multilayer wiring printed board was manufactured (see FIG. 10B).

Example 3 In step (15) of Example 1, spherical silica having an average particle size of 1.0 μm was further used as an inorganic filler.
A multilayer printed wiring board was manufactured in the same manner as in Example 1 except that a solder resist composition was prepared in addition to parts by weight.

Example 4 In the step (15) of Example 1, a spherical silica having an average particle size of 1.0 μm was further added as an inorganic filler.
A multilayer printed wiring board was manufactured in the same manner as in Example 1 except that a solder resist composition was prepared in addition to parts by weight.

Comparative Example 1 As a solder resist composition, 50% by weight of an epoxy group of a cresol novolak type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.) dissolved in diethylene glycol dimethyl ether (DMDG) to a concentration of 60% by weight was acrylic. Photosensitized oligomer (molecular weight: 4000) 4
6.67 parts by weight of 80 dissolved in methyl ethyl ketone
6.67 parts by weight of a bisphenol A type epoxy resin (manufactured by Yuka Shell Co., Epicoat 1001) of 1.6% by weight, and an imidazole curing agent (manufactured by Shikoku Chemicals Co., Ltd., 2E4MZ-CN) 1.6% by weight.
Part by weight, 4.5 parts by weight of a bifunctional acrylic monomer (R604, manufactured by Nippon Kayaku Co., Ltd.), which is a photosensitive monomer, and 1.5 parts of a polyvalent acrylic monomer (DPE6A, manufactured by Kyoei Chemical Co., Ltd.)
0.36 parts by weight of a leveling agent (manufactured by Kyoei Chemical Co., Ltd., Polyflow No. 75) composed of an acrylic ester polymer is placed in a container, stirred and mixed to prepare a mixed composition. 2.0 parts by weight of benzophenone (manufactured by Kanto Kagaku) as a photopolymerization initiator, 0.2 parts by weight of Michler's ketone (manufactured by Kanto Kagaku) as a photosensitizer, DM
A multilayer printed wiring board was manufactured in the same manner as in Example 1 except that a solder resist composition having a viscosity adjusted to 1.4 ± 0.3 Pa · s at 25 ° C. was prepared by adding 0.6 parts by weight of DG. did.

Comparative Example 2 A multilayer printed wiring board was manufactured in the same manner as in Example 2, except that the same solder resist composition as in Comparative Example 1 was prepared.

Next, Examples 1 to 4 and Comparative Examples 1 to 2
The multilayer printed wiring board manufactured in the above was evaluated by the following methods for flame retardancy, opening properties, the occurrence of peeling between the solder resist layer and the conductor circuit and the occurrence of cracks in the solder resist layer, and the results were evaluated. The results are shown in Table 1.

[0160]Evaluation method  (1) Evaluation of flame retardancy The multilayer printed wiring board is cut in accordance with UL94 standard.
And perform a flame retardancy test by the vertical method.
To evaluate. The dimensions of the test piece were 12.7 mm × 1
27 mm × specified thickness.

Evaluation Criteria ：: Passed the criterion of 94V-0. X: Failure of the criteria of 94V-0.

(2) Evaluation of Opening Properties In Examples 1 to 4 and Comparative Examples 1 and 2, after forming an opening in the solder resist layer and curing the same, the shape of the opening before forming a plating layer in the opening was determined. Is observed under a microscope, and further, after the production of the multilayer printed wiring board is completed, the multilayer printed wiring board is cut at a portion where solder bumps are formed, and the cut cross section is observed under a microscope to form a solder resist layer. The cross-sectional shape of the opening thus formed is observed with a microscope and evaluated according to the following evaluation criteria.

Evaluation Criteria 開口: The shape of the opening in plan view is desired, and there is no resin residue on the conductor circuit surface exposed from the opening. ×: The shape of the opening is tapered, and there is a resin residue on the surface of the conductor circuit exposed from the opening, or the opening is unopened.

(3) Observation of Existence of Peeling or Cracking In the same manner as in (2) above, the multilayer printed wiring board is cut, and the cross section thereof is microscopically observed, whereby the gap between the solder resist layer and the conductor circuit is obtained. To observe whether peeling has occurred, and to observe whether cracks have occurred in the solder resist layer. In addition, the above-mentioned multilayer printed wiring board is maintained at a temperature of −65 ° C. for 3 minutes and then maintained at a temperature of 130 ° C. for 3 minutes.
000 times repeated heat cycle test, then
In the same manner as above, it is observed whether or not peeling has occurred between the solder resist layer and the conductor circuit, and further, whether or not cracks have occurred in the solder resist layer.

[0165]

[Table 1]

As shown in Table 1, the multilayer printed wiring boards manufactured in Examples 1 to 4 pass the 94V-0 criterion in the UL94 test standard. Also,
The solder resist layer formed on the multilayer printed wiring board has excellent opening properties, and does not cause cracks or peeling off from the conductor circuit. In contrast, the multilayer printed wiring boards manufactured in Comparative Examples 1 and 2 did not pass the 94V-0 criterion because of the long burning time,
It is inferior in flame retardancy.

[0167]

As described above, the multilayer printed wiring board of the present invention is excellent in flame retardancy, has high adhesion between the solder resist layer and the conductor circuit, and has a solder hole having a desired shape. It has a resist layer.

[Brief description of the drawings]

FIGS. 1A to 1D are cross-sectional views showing a part of a manufacturing process of a multilayer printed wiring board according to the present invention.

FIGS. 2A to 2D are cross-sectional views showing a part of a manufacturing process of the multilayer printed wiring board of the present invention.

FIGS. 3A to 3D are cross-sectional views illustrating a part of the manufacturing process of the multilayer printed wiring board according to the present invention.

FIGS. 4A to 4C are cross-sectional views showing a part of the manufacturing process of the multilayer printed wiring board of the present invention.

FIGS. 5A to 5C are cross-sectional views showing a part of the manufacturing process of the multilayer printed wiring board of the present invention.

FIGS. 6A to 6D are cross-sectional views showing a part of the manufacturing process of the multilayer printed wiring board of the present invention.

FIGS. 7A to 7D are cross-sectional views showing a part of the manufacturing process of the multilayer printed wiring board of the present invention.

FIGS. 8A to 8D are cross-sectional views illustrating a part of the manufacturing process of the multilayer printed wiring board according to the present invention.

FIGS. 9A to 9C are cross-sectional views showing a part of the manufacturing process of the multilayer printed wiring board of the present invention.

FIGS. 10A and 10B are cross-sectional views showing a part of the manufacturing process of the multilayer printed wiring board of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 Interlayer resin insulation layer (resin layer for forming a roughened surface) 3 Plating resist 4 Lower layer conductor circuit 4a Roughened surface 5 Conductor circuit 6 Opening for via hole 7 Via hole 8 Copper foil 9, 29 Through hole 9a Roughened surface DESCRIPTION OF SYMBOLS 10 Resin filler 12 Electroless copper plating layer 12a Ni metal layer 12b Cu metal layer 13 Electroplating layer 14 Solder resist layer 15 Nickel plating layer 16 Gold plating layer 17 Solder bump 19 Solder 20 pin

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Yukihiko Toyoda 1-1, Ibigawa-cho, Ibi-gun, Gifu Prefecture Ibiden Ogaki-kita Plant F-term (reference) 4J036 AD08 AD22 DC41 EA02 EA03 EA09 FA03 FA05 FB03 HA02 JA10 5E314 AA25 AA27 AA32 AA42 BB06 EE02 FF05 FF17 GG26 5E346 CC04 CC09 CC10 CC12 CC14 CC16 CC32 DD25 DD47 EE39 FF07 FF13 GG15 GG27 HH40

Claims (6)

[Claims] 1. A multilayer printed wiring board in which a conductor circuit and a resin insulating layer are sequentially formed on a substrate, and a solder resist layer is formed on an outermost layer, wherein the solder resist layer is made of a P atom-containing epoxy resin. A multilayer printed wiring board characterized by including: 2. The multilayer printed wiring board according to claim 1, wherein said P-atom-containing epoxy resin is an epoxy resin having a divalent phosphoric acid residue and having epoxy groups at both ends. 3. The epoxy resin having a divalent phosphoric acid residue and having epoxy groups at both ends is represented by the following general formula (1). 3. The multilayer printed wiring board according to claim 2, wherein X ¹ and X ² each represent O or a single bond. 3. 4. The multilayer printed wiring board according to claim 1, wherein the P atom-containing epoxy resin is an epoxy resin having a monovalent phosphoric acid residue at one end and an epoxy group at the other end. 5. A monovalent phosphate residue at one end,
The other epoxy resin having an epoxy group at one terminal is represented by the following general formula (2): 5. The multilayer printed wiring board according to claim 4, wherein X ³ is O or a single bond, and R represents an alkyl group having 2 to 8 carbon atoms. 6. The solder resist layer contains at least one selected from the group consisting of a silicon compound, an aluminum compound and a magnesium compound.
5. The multilayer printed wiring board according to any one of 5.